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Genetics

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2. Mendel's Laws of Inheritance

Inheritance in Diploids and Haploids

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Diploid Genetics

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Hello everyone in this lesson. We are going to be talking about deployed genetics and the genetics of deployed organisms as a whole. So deployed genetics is going to be referring to genetics dealing with organisms that have two sets of chromosomes or deployed organisms and understanding the illegal combinations that these organisms can have is extremely important to understanding genetics and deployed genetics as a whole. And there are many important terms I want you guys to remember and the important terms that you guys will learn very quickly because we use them all the time in genetics are going to be things like alleles, Dominic recessive, homosexuals and heterosexuals. Don't worry about memorizing these because you will eventually memorize them because we use them so often. So what are alleles alleles are going to be variants of a particular trait. But more specifically, alleles are going to be versions of a gene. So you can have a gene, let's say it's for eye color and you can have different versions of that same gene that determine eye color. And these are going to be alleles. Alleles are unique versions of the same gene or variants of a particular trait. And deployed organisms are going to have two alleles per gene and I'll explain why in just a sec now these alleles or versions of genes can be dominant and they can be recessive. Now there are more complicated versions of this. We will also talk about co dominance, incomplete, dominance sex linkage and other things like that. Don't worry about that as of yet. Right now, I just want you to know the difference between dominant and recessive alleles Now dominant alleles are going going to be alleles that when they are present are always expressed. So a dominant trait is always seen when it is present. Now a recessive allele is not always expressed when it is seen or when it is present, it is only going to express a recessive trait or phenotype when it is homesickness. So now let's talk about the difference between homosexuals and heterosexuals. Ho Messias means that there are two of the same alleles. Hetero zegaS means there are two different alleles. So let's have a look at an example. Now these are going to be two sets of chromosomes. Now I know that these chromosomes are from a deployed organism because remember a deployed organism is going to have a ploy t of two in employee is referring to the number of chromosomes or the number of sets of chromosomes that an organism has deployed is represented by two in and deployed organisms have two sets of each chromosome. So for example, let's say that an organism has three unique chromosomes. If that organism is deployed, it will have one and two of the first chromosome. So this is the number one chromosome and has two versions and it is going to have two versions of the number two chromosome and it is going to have two versions of the number three chromosome. This is a deployed organism because it has two sets of each chromosome and has two versions of the same chromosome. We are these types of organisms. We have two of each of our chromosomes. If you guys look at chromosome number one, your cells will have to chromosome number ones to chromosome number two to chromosome number three and so on and so forth. Now we also have hap Lloyd genetics which we will learn more about later. Hap Lloyd genetics means that they only have one of each chromosome. So one of each chromosome. So these cells, let's say if they had three unique chromosomes, three unique chromosomes, then if they have three unique chromosomes, what is that going to look like? Well, they're going to have one chromosome number one, they're going to have one chromosome number two and they are going to have one chromosome number three and the chromosomes are going to be represented by these lines. So these are the chromosomes that is a chromosome and that is a chromosome. So hap Lloyd genetics, there's only one of each chromosome deployed genetics. There's two of each chromosome. Now, whenever there are two of each chromosome, that means that you can have two different versions of that same chromosome and this is where different alleles or different versions of genes are going to come in because the same chromosome. So if you have to number one chromosomes, they have the same genes on them. But they might have different alleles for those jeans on them and this is going to be what makes an individual homosexual or heterosexual for a particular gene. So let's look at this individual right here and we can see that these are going to be the same chromosomes. So let's say these are both chromosome Number one, which means they have the same genes. But that does not mean that they have the same alleles. But in this particular case they do because we can see, it says that they're homos I guess. So you can see that both of these individuals have this black a little for that particular gene. So they have the same allele. They have identical alleles. So this individual is a homosexual individual right here. Now let's look at the same scenario. But now let's look at a heterocyclic individual. This individual has two unique alleles. So these are different alleles four the same jean. And this can happen in deployed genetics because you have two versions of the same chromosome which are going to hold the same genes. But each of these two chromosomes can have unique alleles or unique versions of those genes, which is why you can end up with a hetero six individual who has different versions of the same genes. So that is the basis behind deployed gin and guys, I just wanted you to know that a locus is going to be the specific location of a gene on a chromosome. So this is a locus. It is the specific location of that particular gene and each gene is going to have its own unique locus. Alright, so now let's scroll down and we're going to talk about some more specific details. Okay, Alright, so jeans obviously lie on what genes obviously are going to lie on chromosomes. We already talked about that. So chromosomes are going to be segments of DNA that holds very specific genes and the number of chromosomes is going to vary between the different species of organisms. And they're going to hold the genes now in deployed cells. Like I said, there are two chromosome copies for each type of chrome. Remember up here we said that in this individual there are two number ones. There are two number twos and there are two number threes. That's because this individual is deployed. They have two of each chromosome and that's what deployed means. So deployed cells, there are two chromosome copies of each type of chromosome and each chromosome contains one alil they can be the same or they can be different. So now what's going to happen whenever the cell divides? Well during mitosis, these chromosomes are going to be replicated and they're going to be divided. Remember may aosis is going to be the creation of gametes and this is going to be a very special type of cell division because it's not going to create deployed cells whenever we talked about mitosis, remember mitosis creates deployed cells. So that means that the number of chromosomes is retained but in mitosis we're going to make Hap Lloyd sells. So now these cells which are created which are going to be called gametes or sex cells are only going to have one of each chromosome where our normal body cells are somatic cells have two of each chromosome. So during my Asus these chromosomes are going to be replicated once but then they're going to be divided twice. Now in mitosis they are replicated once and divided once in mitosis replicated once, divided twice. And because they are divided twice, you're going to have half the number of chromosomes in these sex cells than the body cells. So these sex cells are going to be hap Lloyd. Okay, so now let's scroll down and let's look at the process of mitosis. This is just going to be a very basic overview of the process of mitosis. Do not worry, we will go into mitosis in much more depth in later lessons because it is a very important process, especially in genetics. But I just wanted to give you an overview of the processes that you will see and how deployed and hap Lloyd genetics come into play. Alright, so let's start off and the first thing we're going to start off with is our first deployed cell that is going to be utilized to make these Hap Lloyd gametes. So this is the first cell and I'm going to circle it just so it's a little bit easier. So this is a cell a deployed sell and it is going to only have one chromosome. But because it's deployed it has two sets of these chromosomes. So it has two chromosomes. Now this representation sometimes you will see it represented this way chromosomes represented this way. But I'm also going to draw another way that you guys will commonly see chromosomes replicated or represented but it will be the same thing. So what I'm gonna do is I'm going to draw the counterpart over here. So these are gonna be the same cells. So these are the same. So we have our chromosomes and we're gonna have one chromosome and the second chromosome. And remember this is also a deployed cell and the starting cell. So the starting deployed cell only has one chromosome which I'm just gonna shorten to chrome but it has two copies of this chromosome because it is deployed. Okay now in our deployed cell you can see that this individual is heterocyclic. So let's also write that this individual is heterocyclic this and that means that their genotype is going to be a dominant A and a recessive A. So they're heterocyclic. They have one of each type of khalil. Now I'm also going to write that here. So you guys can see it here. This is the same representation. I commonly see the stick representation which I am drawing for you. I've seen that a bunch. This is also a very common representation. I wanted you guys to see both ways that you could draw these particular cells. Because a lot of the time on test questions for mitosis and mitosis especially dealing with chromosomes. Your professor might draw out and you will have to recognize what they are actually drawing. So I wanted to show you both ways that they could draw this particular process. Okay, so we have our starting sell. It is hetero I guess it has two different versions of the same gene. So it has two different alleles. It only has one chromosome but because it has two copies of the same chromosome, it is a deployed cell. Now. Just so you guys know the two copies of the same chromosome are called a homologous pair. So these guys so two copies of the same chromosome are homologous pair. Okay, alright. So we have our homologous pair. Now we're going to go to the step of replication. So the D. N. A. Is going to be replicated. So let me scroll down a little bit. So now this is still in that cell. The cell is not divided as of yet. We still have our deployed. So now what is that going to look like in the stick notation. So you guys can see that up here. I drew them as simple sticks but whenever the chromosomes are replicated in the kind of stick notation, they're going to now look like this. They're gonna have this X formation and this is still a deployed sell but is a replicated deployed cell. So now there are copies the DNA has been copied. So as you guys can see here we have two copies. Let me use a different color. We have two copies of the chromosome with the dominant allele and we have two copies of the chromosome with the recessive allele. Same thing is happening over here. Let me draw that out for you guys. Same thing is happening over here. It's just denoted a little bit differently. Generally whenever you see this drawn out it's going to be in the X formation because these chromosomes are actually stuck together. They're not separated as you see in this particular notation. So in this step we are still seeing a deployed cell but now it has been replicated. So the D. N. A. Has been replicated. And now you're going to have this thing called sister chroma tides. Sister chroma tides are going to be genetically identical versions of the same chromosome. So these are going to be sister chroma tides. These are the chromosomes that were made whenever it was replicated. So those are sister chroma types and these are sister chroma tides. These are the identical versions of the same chromosome that were generated via replication. So sister chromosomes are genetically identical replications of the same chromosome. Now these genetically identical replications of the same chromosome are commonly called a diadem and the replicated version of the homologous pair is going to be called a tetrapod? Generally we only utilize the term tetrapod when we're talking about my Asus or when we're talking about crossing over, which you guys will learn about later. But I just wanted you guys to have this terminology. So to sister to sister chroma tits is call called a diet. But to replicated homologous pairs is called a tetrapod. So now we have replicated the D. N. A. What is going to happen? We are going to move on to the first division. Remember that May Asus has a division one and it's going to have a division two. So now what is going to happen? Well in the first round of division of mitosis, the homologous pairs separate into two different cells. So homologous pairs separate into two unique cells. So now this set or this chromosome is in one cell and this chromosome is in another cell. Same thing is going to be happening over here. We're going to have just so you guys have for reference remember they were excess. There's still going to be X is over here. They were separated. So now we have one set of sister chroma tides in one cell and another set of sister chromatic in another cell. So the homologous pairs or the matching chromosomes have been separated but the sister chroma tides have not been separated as of yet. So now, what does this result in the result from this is the cells are now hap Lloyd. This is best represented over here. The cells are now hap Lloyd and you guys can see why because they only have one of each chromosome inside of the cell. This model here can be a little confusing because it kind of looks like there's two of each chromosome in the cell. But that's not really true. There's two sister chroma tides of each chromosome in a cell and sister chroma tides are not considered chromosomes on their own until they have been separated. But it makes better sense for me, especially in the stick model, you guys can see over there, there's one chromosome in each sell and that means it is a Hap Lloyd sell now which you guys can see in the employee right here they are in they are Hap Lloyd sells. Now what's going to happen? The second round of division? Remember in mitosis, the cells divide twice. So now this is a cell. This is a cell. This is a cell. And so is this So what is this going to look like over here is going to be this. So now we're going to go back to that single stick that we started with. And now that the sister Chroma tides have separated, they are considered their own chromosome. So now we are going to have these cells let me I'm gonna go out of the picture so I can have room to Right So now we're going to have these cells and the sister chroma tides did not spell that right chroma tides separate. And we have hap Lloyd gamut cells. So now we have four hap Lloyd gamete cells and we have one of each type of chromosome in these particular cells. And this is going to be the basic overall process of mitosis which takes a deployed cell replicates. Its D. N. A. Then divides that sell twice to make four genetically unique hap Lloyd gamete cells. So don't worry if this seems a little much we will learn more about mitosis and the specific processes and how these chromosomes are going to separate in more detail in later lessons. Okay so now that we've gone over my aosis, let's scroll down and let's talk about the distinct characteristics of chromosomes. Because you are going to have to know the distinct characteristics of chromosomes. Okay so chromosomes have a distinct structure. They certainly do. And the very interesting part of their structure which can be unique to different types of chromosomes is going to be the centrum ear and its location the centrum here is going to be a condensed region of the chromosome. It's actually very specialized D. N. A. That condenses very tightly. And what's important about this central mirror is that it is going to hold the sister chroma tides together. Remember we just talked about sister chroma tides and that is going to be the replicated version of the same chromosome. They're gonna be held together by the centrum ear. So they hold sister chroma kids together and they allow the chromosomes. So I'm just gonna take chrome's to be moved. So actually the kinetic core processes and the micro tubules that actively grab onto the chromosome and pull them apart. This is where they're going to attach to the chromosomes at the central mirror. That's a very specialized location of condensed D. N. A. That holds the sister chroma tides together and allows the main topic spindle or myopic spindle to actually grab onto the chromosome and move it around. So the centrum ears allow the sisters to stay together. And it also allows this chromosome to be moved around. Now there are different locations of the centrum ear and the particular too. Type of chromosome can commonly be distinguished by the location of its central here. So you can have medicine trick or central centrum ears. You can have sub medicine trick or slightly off center centrum ears. You can also have acro centric, which means these are going to be at one end. And I wanted to add one more in here for you. We can also have Tello centric. Do you guys know what Attila mirror is till a mirror is going to be the region of DNA at the very, very ends of your chromosomes and Tyla centric, central mirrors are going to be at the very end of your chromosomes. So these are on the terminal end. And I believe humans don't have tele centric chromosomes. But many organisms do. We generally have medicine trick? Sub meta centric and afro centric. I don't believe we have tele centric chromosomes but they do exist. So I wanted to give you that information. So those are going to be the four different types of locations for the central air. And depending on where the central is located, One end of the chromosome or one arm of the chromosome is going to be longer or shorter than the other. And there are two different arms on a chromosome. The p arm and the Q arm. Now the p arm is going to be the shorter arm. And I believe P just stands for the petite arm or small arm. I believe I read that somewhere and the Q arm is going to the longer arm. I don't know why I. Q. Designates longer. I just remember P for petite or small. So the p arm is going to be shorter than the Q arm unless you're talking about a medicine trick or even in the middle centrum here. So the length of these arms of the chromosomes is going to be determined by where the centrum here actually is. So in this representation we can see that in the medicine trick, the centrum ear is right in the middle. So in this particular um scenario, the p arm, nope. That's not right. The p arm is equal to the length of the Q. Arm. So P equals Q. So we would say this this is P and this one's cute and they're exactly the same. Now. Sub medicine trick. Remember that means slightly off center, which you guys can see here. That means the p arm or the small arm must be the one on the top. So this is P. And this is Q. And its sub medicine trick, P is smaller than Q. Now in akra centric. This is even more distinguishable. You can see the P arm is tiny and the centrum ear is very close to the end. So the p arm is smaller than the Q. Arm. And what would this look like in a tele centric example? This would be a tele centric. Oh, sorry about that guys. This would be a tele centric example. And I suppose that the p arm is just non existent and there's only a queue arm and the central here is all the way at the end of the chromosome. So what would this look like? So these are not replicated? Let's write that Not replicated. What would this look like if the chromosomes had replicated? And they had sister chroma tits? Okay, because that is very important. So what would this look like? So I'm going to draw this as the stick formation because that's how most replicated chromosomes are represented. So these meta centric, let's see if I can get this in the middle. So this is what the medicine trick would look like. The central mirror is right in the middle and you can see those sister chroma kids. So these are the sisters. So we have our replicated chromosomes are replicated sisters that are connected via the central near to one another. Now, what would the sub medicine trick replicated chromosome look like? It would look like this where slightly off center. The Q arms are slightly longer than the p arms. So these are the P and Q. P and Q. Now, what is the acro centric going to look like? Even closer to the end? Looks kind of funny, even closer to the end. And finally tele centric is going to look like this and you should only have a cute arm and that is going to be what a replicated chromosome will look like based on its central location. So you guys can obviously see that we could pretty easily determine what types of chromosomes we're looking at based on the location of their centrum ears. Okay, everyone that's all I have for you on deployed genetics. Hopefully it was, it was very self explanatory and hopefully these notes helped. But now let's go on to talk about hap Lloyd genetics and other genetic topics
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Haploid Genetics

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Okay. So now let's briefly talk about half Lloyd genetics. We're just going to briefly do this because first it's not as complicated and to it, we're not gonna cover half Lloyd's as much in this class. But in half Lloyd sells there's only one allele per gene which again makes things simpler. Now, Wild type and mutant alleles in this case have different symbols than what you may be familiar with. So, wild type allele is gonna look like it's supposed to be highlight wild type of girl is gonna look like this. So it's a lower case letter with a plus sign. Now the plus sign super important dictates wild type. You see that that's the normal version. That's the wild type. The mutant. A leo on the other hand, lacks that plus side. So you see there's a plus sign here, no plus sign here. That's how you tell the difference between wild type and mutant and Hap Lloyd's. So what happens is that there's half Lloyd's made in a variety of different ways. One of the ones that's mentioned in your book is the one I'm going to present. And so this is, it says we know an opposite mating types view. So if you have a wild type and a mutant, so what would that look like that would look like a plus a there's a little cheap for you there. It can actually, so when those two mate together, it actually can create a deployed cell called a Maya site and this is gonna look exactly like this. That's how you're gonna write the genotype for that. Now these generally are replicated and then divided to create more half Lloyd cells that then continue the species. Like I said, this is only one way that half Lloyd cells made. But this is I guess a good overview or a good example of what this would look like. So here we start with our half Lloyd cells. We have our one allele. This is the wild type and therefore this is the mutant. And how do we know which one is which? Right? That's the because of the plus sign. The wild type has the plus sign. When these are mating they confuse together. Then get this bigger hap Lloyd cell with both the wild type of the mutant it replicates. So then you get now four alleles to wild types and two mutants and then it can divide and when it divides it will create four hap Lloyd cells to wild types and two mutants. So just one example of hap Lloyd genetics. But the important thing here it's really to understand that half always have one allele and their notation is a little bit different with the plus sign and without the plus sign. So with that let's now turn the page
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Problem

Which of the following describes an acrocentric chromosome?

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Problem

In diploid organisms there are _______ chromosomal copies. In haploid organisms there is _______ chromosomal copy.

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Problem

After a diploid cell undergoes meiosis, it divides to produce…

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